Finder-starting system



0. L. GOODRUM.

FINDER STARTING SYSTEM.

APPLICATION FILED SEPT-'22, 1916.

Patented Feb.- 10, 1920.

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CHARLES L. eoonnum, or BROOKLYN, NEW roan, assrenon 'ro wnsrnnn nLEoraIo' comranxinooaronarnn, or new roan, n". Y., a CORPORATION on NEW YORK.

FINDER-STARTING SYSTEM.

Specification of Letters Patent. I Patented Feb. 10, 1920.

' Application filed $eptember 22, 1916. Serial No.l121,572.

To all whom it may concern:

Be it known that 1, CHARLES L. GroooRUM,

' a citizen of the United States, residing at switches, and more particularly to systems,

in which a starter wire arrangement is used in conjunctionwith such switches. V

The object of the present invention is to provide an arrangement whereby calls originating in the same group may be handled at an increased speed.

Heretofore in. systems employing line finders, it has been the practice to permit only one finder to start seeking a calling line in a given group at a time. Although means have been provided for responding immediately to a second call if in 'a group other than that of the first calling line, means have been provided for delaylng the response to the second call when in the same group, in some systems until the'first calling line has been reached, in other systems until a time measuring switch has been fully operated in order to measure an interval slightly greaterthan the time required for the brush set to travel to'the last line of a group, and

in certain systems until the first switch to be started has moved out of its normal position.

A feature of thepresent invention is the provision of means for starting a number of line finders simultaneously when a number of calls in the same group are originated at the same time. Thisis accomplished by the operation of a marginal relay which fails to operate when only one call is present. The actuation of this relay results in placing ground on the out-starter wire immediately, without waiting for the instarter wire to be extended thereto, as is usual in systems of this type.

The invention as shown is arranged for use with a circuit arrangement such as shown in Patent No. 1,147.390, issued July 20, 1915. The switch structure in the present embodiment is, however, of the aroundand-up type, whereas the structure of the 1 switch in the above mentioned patent is of the well-known up-and-around type. This necessitates no change in circuit arrangement, the only change being that instead of using a group multiple commutator whose segments are arranged inastraight line, a connnutator whose segments are arranged in a circle is used.

his thought that the invention willflbe best understood from the following detailed description, reference being had to the accompanying. drawing.

' In the drawing the lines of two calling subscribers in the same group are represented, together with such portions of a finder circuit and starter wire arrangement as are necessary to an understandlng of the invention.

If the subscriber at substation l desires to initiate acall. he removes his receiver from the hook, whereupon line relay 2 is.

completes ac'ircuit for group relay 4 from v grounded battery, winding ofrelay 4, con ductor 5, resistance 6, to ground at the armature and front contact of relay 2. Relay 4 is energized and attracts its armatures.

The attraction of the left-hand armature of relay 4 completes a circuit for group relay 7, but this relay. being marginal, does not operate, dueto the presence of resistance 6. The outer right-hand armature and front contact of relay 4 supplies ground through contact 8 of the finder indicated to the right of the dotted line to the primary magnet of such switch. The primary magnet of the switch is operated over circuits such as disclosed in the previously mentioned Patent No. 1,147,390. When commutator brush 9 arrives on a segment 10 on which there is no ground, due to the actuated condition of relay 4, the circuit of the primary stepping magnet will be permanently interrupted and the brush set 11 will be positioned in proper relation to the group of terminals containing the calling line. The side switch, one of whose wipers is indicated at 12, is movedinto position '2.

end call coming in at this time will start a.

succeeding finder whether such call is originated in the group shown or n a preceding group. r

If it should happen that the subscribers at sub-stations 1 and 21 should originate calls simultaneously, line relays 2 and 22 will be energized in the well-known manner. Group relay 4: will be energized as pre both switches, whereupon it will viously described. A' circuitis completed at this time for relay 7 from grounded battery, winding of relay 7 left-hand armature and front contact of relay 4,'to ground, through resistances 6 and 26 in parallel. The reduced resistance in this path allows marginal relay 7 to energize, whereupon a circuit is completed from ground, armature and front contact of relay 7 side-switch wiper '12 in its first position, out-starter wire 16, to the primary magnet of the next idle finder. The actuation of relay t starts the finder shown in the drawing as previously described, and it will therefore be seen that two finders have been started at the same time.

A call coming in from a precedinggroup over in-starter wire 15 will await the arrival of side-switch wipers 12 in position 3 at start the finder normally allotted to the second suc- .(:eeding group, if idle. WVhen the lines are found, the deenergization of line relays 2 and 22 breaks the circuit of relay 4 which deener 'izesand opens in turn the circuit of ,relay 7 The deenergization of relay 4 places ground on group commutator segment 10 to indicate the non-calling condition thereof. Group relays 4: and 7 may now be. againactuated in response to other originating in the same group.

, busy,

calls At conclusion of the conversation anactuated finder is restored in the manner set forth in the previously mentioned patents.

What is claimed ,is:.

1. In a telephone exchange system, a plurality of calling substation lines arrange in groups, a plurality. of finder switches serving said lines, there being a finder switch normally assigned toeach of said roups, and means tostart a plurality of nders simultaneously in search of lines calling in the same group at the same timel In a telephone exchange system, a plurality of calling substation lines arrangedin groups, a plurality of finder switches serv-- ing said lines, a relayfor each of said groups to control the starting of one of said finders, a second group relay-to control the starting of a second finder, andv means to energize said second relay only when more than one call is present in the group with which it is associated.

3. In atelephon e exchange system, a; plurality of calling substation lines arranged in i a plurality of finder switches serva relay for each of said group relay controlled at means to start groups, mg said lines,

groups, a second contacts of said first relay,

two of said finders simultaneously when.

both of said relays are energized, and means to energize both of said relays when more than one call is present in the group with which said relays are associated.

a In a telephone exchange system, a plu rality of calling substation lines arranged in groups, a plurality of finder switches serving said lines, there being one of said finder switches normally assigned to each of said groups, a starter wire circuit to control the starting of the switch of a succeeding group when the switch'normally assigned to the group in which the call originates is means to extend said starter wire to a succeeding switch when a calling line is seized, and means to operate a succeeding switch without awaiting the extension of the starter wire when two callsare originated in the same group at the same time.

.In witness whereof, I hereunto subscribe my name this 19th day of September A. D., 

